This invention relates to a traveling wave tube amplifier arrangement. More particularly, the present invention relates to an operating point stabilized, linearized traveling wave tube transmission amplifier arrangement including a traveling wave tube amplifier having a predistortion circuit for providing compensation for the non-linearities in the traveling wave tube amplifier and a preamplifier with a limiter connected in series with the amplifier input.
To compensate for the non-linearities in traveling wave tube amplifiers, which non-linearities cause undesirable intermodulation products in multi-carrier operation, predistortion circuits are usually superposed on the traveling wave tube amplifier.
Such predistortion circuits, whose amplitude and phase transfer characteristics are the inverse of the characteristics of traveling wave tube amplifiers, are known, for example, from European Patent No. EP 47 825, granted Oct. 3, 1984 and from a paper by G. Satoh et al, "Nonlinear Satellite Channel Design for QPSK/TDMA Transmission", 5th International Conference of Digital Satellite Communications, Mar. 23-26, 1981, Genoa, Italy. From the latter publication it is also known to connect a limiter network in cascade with a predistortion circuit. However, operating point changes due to ambient temperature changes and aging phenomena degrade the linearization process of such a traveling wave tube amplifier.